The Vermont senator had lost significant momentum to the former US secretary of state following last week's Super Tuesday vote, after which Clinton gained a sizeable lead in the count for delegates needed to secure the Democratic nomination.

But he seemed to recover somewhat with the two key victories yesterday, ahead of another contest in Maine.

US broadcasters projected Hillary Clinton would be the victor in the night's only Democratic primary, in the southern state of Louisiana.

Sanders lost no time crowing about the Kansas victory in a fundraising appeal in which he expressed delight over his "political revolution."